Installing APC on RHEL5

Here's how to install APC on RHEL5.
# yum install php-pear php-devel httpd-devel
# pecl install apc
# echo "extension=apc.so" > /etc/php.d/apc.ini
# service httpd restart


Check for the apc section in your phpinfo() page. If it's not there:

# tail /var/log/httpd/error_log
[Tue Aug 12 15:43:59 2008] [notice] Digest: done
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php/modules/apc.so' - /usr/lib/php/modules/apc.so: cannot open shared object file: Permission denied in Unknown on line 0


SELinux is preventing the extension from loading, I'll bet. Let's check:

# tail /var/log/messages
Aug 12 15:42:40 mybox yum: Installed: httpd-devel - 2.2.3-11.el5_1.3.i386
Aug 12 15:44:01 mybox setroubleshoot: SELinux is preventing the httpd from using potentially mislabeled files (./apc.so). For complete SELinux messages. run sealert -l 9e4bbfa8-327b-4bb2-94df-f154045a1ef1


Let's view the security contexts for our PHP extensions:

# ls -Z /usr/lib/php/modules
-rwxr-xr-x root root root:object_r:tmp_t apc.so
-rwxr-xr-x root root system_u:object_r:textrel_shlib_t dbase.so
-rwxr-xr-x root root system_u:object_r:textrel_shlib_t gd.so
...


Yup. Notice how the security context is missing (it's tmp_t for apc.so). Let's fix that.

# restorecon /usr/lib/php/modules/apc.so
]# ls -Z /usr/lib/php/modules
-rwxr-xr-x root root system_u:object_r:textrel_shlib_t apc.so
-rwxr-xr-x root root system_u:object_r:textrel_shlib_t dbase.so
-rwxr-xr-x root root system_u:object_r:textrel_shlib_t gd.so
...


Now let's try again:

# service httpd restart


Yay!

P.S. On x86_64, apc.so is in /usr/lib64/php/modules.